1. Field of the Invention
The invention relates to the field of heat exchangers and in particular to a heat exchanger for a shower installation and a shower tray, according to the preamble of the respective independent patent claims.
2. State of the Art
GB2416829A shows a heat exchanger for a shower tray, in which the waste water flows through a box, through which a meandering feed pipe with fresh water leads. In the embodiment of FIGS. 3-6, waste water flows via a heat exchanger box, whose surface is provided with ribs (21, 33) which act as flow inhibitors and effect a meandering course of the waste water across the heat exchanger.
In the heat exchanger of NL 1015561 C2, a tube for the fresh water is led through a channel with the waste water, wherein the waste water channel is shaped out in a plastic shell.
NL 1009927 C2 shows a heat exchanger, in which the waste water runs off via a cone-like sheet metal part with pipes with fresh water which are attached thereabove or therebelow. In another embodiment, the fresh water is led between two cone-like plates which are distanced from one another and via which the waste water runs away. This embodiment may, however, not withstand a high pressure of the fresh water, as is required according to the regulations of the respective authorities.
DE3319638A1 shows a heat exchanger which is inserted into a shower tray of the tray base. A spiral-shaped fresh water conduit is applied into a channel, through which the waste water flows away. In one embodiment, meandering flows are present, which are defined by bent plates and are separated from one another.
WO 2009/101161 A2 as well as WO 2008/155561 A1 likewise describe a heat exchanger arranged below a shower tray. Therein, tubes for feeding fresh water are arranged below the base of a shower tray and waste water flows around them on all sides.
What the heat exchangers from the state of the art have in common, is the fact that the manner in which the waste water is led, leads to a contamination of the waste water course, wherein this is difficult to clean.